- Compute V_min and V_max (extrema) of V_los matrix,
- Create new array V_obs, where velocity values (V_los) range from V_min to V_max, in steps of 1 km/s,

B) We want an output image matrix, OUT(x,y,z), where x_i corresponds to V_obs(i)

- Scan the V_los(x,y,z) matrix; say, V = V_los(x,y,z)
- If V1 < V < V2, then OUT(v,y,z) += rho(x,y,z)
- Repeat a & b for energy and pressure.